背景:轻度甲状腺功能减退症,包括亚临床甲状腺功能减退症(SCH)和孤立的母亲低甲状腺素血症(IMH),在孕妇中相当常见,但其对妊娠结局的影响尚不清楚,尤其是妊娠晚期轻度甲状腺功能减退。
目的:评估妊娠早期和晚期SCH和IMH的影响,分别,产科和围产期结局。
方法:这项大型前瞻性研究在上海国际和平妇幼保健院(IPMCH)进行。从2013年1月至2016年12月,在IPMCH进行了妊娠早期产前筛查的52,027名孕妇连续入选。评估孕早期孕妇SCH和IMH对妊娠结局的影响。根据妊娠早期的甲状腺功能将参与者分为三组:妊娠早期甲状腺功能正常组(n=33,130),妊娠早期SCH组(n=884),妊娠早期IMH组(n=846)。然后,评估妊娠晚期孕妇SCH和IMH对妊娠结局的影响,根据妊娠晚期甲状腺功能正常组分为3组:妊娠晚期甲状腺功能正常组(n=30,776),妊娠晚期SCH组(n=562),和妊娠晚期IMH组(n=578)。产科和围产期结局,包括早产(PTB),先兆子痫,妊娠期高血压,妊娠期糖尿病(GDM),胎龄大(LGA),小于胎龄,巨大儿,剖宫产,测量和比较SCH/IMH组和甲状腺功能正常组的胎儿死亡。二元逻辑回归用于评估SCH或IMH与这些结果的相关性。
结果:34,860名妊娠早期(第8-14周)和妊娠晚期(第30-35周)促甲状腺激素和游离甲状腺素浓度的孕妇被纳入最终分析。与甲状腺功能正常组相比,孕早期孕妇的SCH与GDM的风险较低(aOR0.64,95%CI0.50-0.82)。然而,妊娠晚期SCH与PTB发生率升高相关(aOR1.56,95CI1.10-2.20),先兆子痫(aOR2.23,95CI1.44-3.45),与甲状腺功能正常组相比,胎儿死亡(aOR7.00,95CI2.07-23.66)。妊娠早期的IMH会增加先兆子痫的风险(aOR2.14,95%CI1.53-3.02),GDM(aOR1.45,95CI1.21-1.73),LGA(aOR1.64,95CI1.41-1.91),巨大儿(aOR1.85,95CI1.49-2.31)和剖宫产(aOR1.35,95CI1.06-1.74),而妊娠晚期IMH会增加先兆子痫的风险(aOR2.85,95CI1.97-4.12),与甲状腺功能正常组相比,LGA(aOR1.49,95CI1.23-1.81)和巨大儿(aOR1.60,95CI1.20-2.13)。
结论:这项研究表明,虽然妊娠早期SCH并没有增加不良妊娠结局的风险,妊娠晚期SCH与几种不良妊娠结局相关.妊娠早期和晚期IMH与不良妊娠结局相关,然而,影响因三个月而异。这些结果表明,妊娠轻度甲状腺功能减退症的时机可能是确定其对不良妊娠结局的影响的关键,并强调了对妊娠中期甲状腺功能进行特异性评估的重要性。
BACKGROUND: Mild hypothyroidism, including subclinical hypothyroidism (SCH) and isolated maternal hypothyroxinemia (IMH), is fairly common in pregnant women, but its impact on pregnancy outcomes is less clear, especially mild hypothyroidism in late pregnancy.
OBJECTIVE: To evaluate the impact of SCH and IMH in the first and third trimesters, respectively, on obstetric and perinatal outcomes.
METHODS: This large prospective
study was conducted at the International Peace Maternity and Child Health Hospital (IPMCH) in Shanghai. 52,027 pregnant women who underwent the first-trimester antenatal screening at IPMCH were consecutively enrolled from January 2013 to December 2016. To evaluate the impact of maternal SCH and IMH in the first trimester on pregnancy outcomes, participants were divided into three groups according to thyroid function in the first trimester: first-trimester euthyroidism group (n= 33,130), first-trimester SCH group (n= 884), and first-trimester IMH group (n= 846). Then, to evaluate the impact of maternal SCH and IMH in the third trimester on pregnancy outcomes, the first-trimester euthyroidism group was subdivided into three groups according to thyroid function in the third trimester: third-trimester euthyroidism group (n= 30,776), third-trimester SCH group (n= 562), and third-trimester IMH group (n= 578). Obstetric and perinatal outcomes, including preterm birth (PTB), preeclampsia, gestational hypertension, gestational diabetes mellitus (GDM), large for gestational age (LGA), small for gestational age, macrosomia, cesarean section, and fetal demise were measured and compared between those in either SCH/IMH group and euthyroid group. Binary logistic regression was used to assess the association of SCH or IMH with these outcomes.
RESULTS: 34,860 pregnant women who had first (weeks 8-14) and third trimester (weeks 30-35) thyrotropin and free thyroxine concentrations available were included in the final analysis. Maternal SCH in the first trimester was linked to a lower risk of GDM (aOR 0.64, 95% CI 0.50-0.82) compared with the euthyroid group. However, third-trimester SCH is associated with heightened rates of PTB (aOR 1.56, 95%CI 1.10-2.20), preeclampsia (aOR 2.23, 95%CI 1.44-3.45), and fetal demise (aOR 7.00, 95%CI 2.07-23.66) compared with the euthyroid group. IMH in the first trimester increased risks of preeclampsia (aOR 2.14, 95% CI 1.53-3.02), GDM (aOR 1.45, 95%CI 1.21-1.73), LGA (aOR 1.64, 95%CI 1.41-1.91), macrosomia (aOR 1.85, 95%CI 1.49-2.31) and cesarean section (aOR 1.35, 95%CI 1.06-1.74), while IMH in the third trimester increased risks of preeclampsia (aOR 2.85, 95%CI 1.97-4.12), LGA (aOR 1.49, 95%CI 1.23-1.81) and macrosomia (aOR 1.60, 95%CI 1.20-2.13) compared with the euthyroid group.
CONCLUSIONS: This
study indicates that while first-trimester SCH did not elevate the risk for adverse pregnancy outcomes, third-trimester SCH was linked to several adverse pregnancy outcomes. IMH in the first and third trimesters was associated with adverse pregnancy outcomes, yet the impact varied by trimester. These results suggest the timing of mild hypothyroidism in pregnancy may be pivotal in determining its effects on adverse pregnancy outcomes and underscore the importance of trimester-specific evaluations of thyroid function.